There are numerous examples of lift axle suspensions in the patent literature, including: U.S. Pat. No. 3,201,141 (Bernstein (1965); U.S. Pat. No. 4,000,913 (Gibson 1977); U.S. Pat. No. 4,256,326 (Cantrell et al 1981); U.S. Pat. No. 5,403,031 (Gottschalk et al 1995); U.S. Pat. No. 5,549,322 (Hauri 1996); U.S. Pat. No. 5,655,788 (Peaker 1997) and U.S. Pat. No. 6,416,069 (Ramsey 2002).
The use of a lift axle suspension enables a driver of a vehicle to lift one or more axles in order to selectively transfer more weight to the tires that remain on the ground. This may be done when the vehicle is loaded in order to increase traction or provide more controlled braking. This may be done when the vehicle is not loaded in order to save tire wear.